Iron bridge



UNITED STATES PATENT OFFICE.

LE\VIS EIKENBERRY, OF EASTON, PENNSYLVANIA.

IRON BRIDGE.

Specification of Letters Patent No. 31,157, dated January 22, 1861.

To all whom it 'may concern:

Be it known that I, LEwis EIKENBERRY, of Easton, in the county of Northampton and State of Pennsylvania, have invented a new and useful Improvement in Iron Bridges; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specication, in which- Figurel, is a side view of a bridge constructed with my improvements. Fig. 2 is a top view of one of the side frames of the bridge. Fig. 3, is a perspective view illustrating a modification of my invention.

Similar letters of reference, in each of the several figures indicate corresponding parts.

In the construction of iron bridges two things are essential, viz: strength and lightness, and these two qualities have not as yet been combined in bridges constructed of cast iron, and in fact the first quality is lacking in those cast iron bridges which are made exceedingly heavy, because cast metal will not bear the strain caused by sudden. eXpansion and contraction, and hence the want of confidence on the part of the public in cast iron bridges or trusses.

My invention is designed to overcome the difficulties experienced with iron bridges,

and at the same time to enable the engineer to erect iron bridges which will be light,

sti'lf and durable at a comparatively small cost. To this end therefore My invention consists 1st in a side frame for a bridge, having its diagonal braces, or diagonals and uprights constructed of angle iron, substantially as hereinafter described.

It consists 2nd in the combination of double angle iron or U shaped diagonal braces with single angle iron uprights or diagonals, substantially as hereinafter described.

It consists 3rd in a side frame for a bridge which has its diagonals or uprights constructed of U shape or double angle iron, as hereinafter described.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A, A, A, represent the main uprights of the bridge. They are made somewhat in form of a U in their transverse section, and terminate, as shown at a, o, c, in solid ends, so as to provide substantial hold fasts for the eye screw bolts el, c, f, of the cables B, B, C, C, as represented.

D, D, are the double angle iron or U shaped intermediate diagonal braces, and E, E, Figs. l and 2, are single angle iron uprights, or if desired they may be made diagonals so as to form a cross with the doublek or with single angle iron diagonals. y The parts D, and E, are pivoted or bolted together as shown at g, g, the bolts passing through the angles L, h, of th'e single angle iron uprights or braces, and through the angles c', c', of the U shaped braces, as shown. These parts thus united form a very light, but very stiff and substantial side frame; the lateral angles of the single angle iron braces, or uprights serving to prevent warping, twisting and collapsing of the frames, and the double angle iron or U shaped braces acting as stiff stays between the inner and outer angle iron uprights or diagonals, and their angles providing two rm. bearings for the bolts or pivots g, g, and thus rendering practicable the passing of the bolts entirely through the frames in a manner that they themselves act as braces to prevent the double angle iron or U, shaped braces from collapsing; and thus it will be seen that the double angle iron or U shaped braces and the lateral angle of the single angle iron uprights or diagonals by acting in concert impart the requisite stiffness to the bridge.

The employment of wrought iron braces in the manner and form described is very important, because they can be manufactured by rolling and consequently are cheap and durable.

The side frames when erected are or may be secured between the main uprights, A, A, A, by means of points or bolts j, j, so as to be able to turn on said pivots, and thus when the compensating arrangement patented by me in 1859 is employed in connection with my present improvement no injurious strain from expansion and contraction will come upon the uprights. t

It will be seenby referring to Fig. 3, of the drawing that the double angle iron or U, shaped braces are made to serve as upright-s, whereas in Figs. l and -2 they are made to serve as the diagonals. The arrangement shown in Fig. 3, makes no material dierence in the strength, lightness or stiffness of the bridge, nor does it alter the character of my invention.

its uprights or diagonals constructed of U shaped or double angle iron-substantially as herein described.

The foregoing specification of my m- 15 provement in iron bridges signed and Witnessed this 3rd day of December 1860.

LEWIS EIKENBERRY.

Witnesses:

ROBT. WV. MFENWICK, Gr. F. Gr. DIETERICH. 

